This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Diabetic retinopathy is a major cause of vision impairment and blindness in the working adult. Mechanistic studies show that oxidative stress and subsequent alteration of signaling pathways are the primarily causal factors in the disease progression. The retinal pigment epithelial (RPE) cell layer is responsible for maintaining the health of the retina by providing structural and nutritional support. Hyperglycemia would cause oxidative stress in the retinal pigment epithelium. A natural mixture of phytochemicals has received much recent attention in prevention of oxidative stress-related eye diseases, including diabetic retinopathy. We hypothesize that wolfberry phytochemicals may act as potential modifiers of the pathology associated with diabetic retinopathy through simultaneous regulation of cell survival/apoptosis pathways, rebalance of cellular fuel homeostasis in the retinal pigment epithelial cell layer. We have found that wolfberry phytochemicals, and its purified fractions, including polysacchardies, have enhanced antioxidant activity in vitro and in vivo. Application of water soluble wolfberry phytochemicals prevents RPE cells from hyperglycemia/oxidative stress damage by scavenging cellular free radicals. In the current proposal, we use both whole extracts and the purified fractions of wolfberry, to treat RPE cells in culture and type 2 diabetic mice. We are determining how wolfberry bioactive compounds protect RPE and/or other retinal cells from hyperglycemia-induced cell apoptosis, are trying to better understand the molecular mechanism on endoplasmic reticulum stress-related retinal degeneration in the type 2 diabetic mouse. The outcome of the current study will lead to the development of complementary therapeutic regimens for prevention or delay the onset of the disease.